Distribution of mycotoxins produced by Penicillium spp. inoculated in apple jam and crème fraiche during chilled storage

Estimations of consumer exposure to mycotoxins through surveillance of mycotoxins in the food trade are well described, but the exposure due to mouldy food in private homes is not known, and may result from removing visible mould on food and eating the rest. In this study, we followed the growth of Penicillium expansum on the surface of apple jam and Penicillium verrucosum on crème fraiche, as well as production and distribution of fungal metabolites throughout the sample (approx. 6 cm high divided into three equal layers), using a multianalyte method, over time (up to 28 days) and at 4, 8 and 15 °C. Growth rates and apparent lag times for P. expansum in apple jam at different temperatures were estimated by fitting to the Baranyi model. The growth rates were 1.7, 2.7 and 4.3 mm day−1 for storage at 4, 8 and 15 °C, respectively; apparent lag times decreased with increasing storage temperature and were 10.6, 7.9 and 2.6 days at corresponding temperatures. Patulin and roquefortine C were identified and quantified, among other fungal metabolites. Patulin was detected in all 2-cm layers of the apple jam at 15 °C. Concentrations in the upper two layers of the jar corresponded to exposures exceeding the health based guidance value (HBGV) for a normal serving size. Consequently, removal of the mouldy part is insufficient to avoid unhealthy exposure. In contrast to patulin, roquefortine C was also produced at 4 °C. The growth of P. verrucosum on crème fraiche was very restricted and could not be modelled. Despite the small colony (8 ± 0.5 mm in diameter), ochratoxin A and citrinin were detected after 21 days at 15 °C in the top 2 cm layer (including the fungal colony), and at concentrations in a normal serving corresponding to an exposure above the HBGV established by EFSA for both mycotoxins. Questiomycin A, an antibiotic, was also produced in crème fraiche but in contrast to the two mycotoxins, was detected throughout all layers of the crème fraiche and was produced also at 4 and 8 °C. As a complement to a previous study, we also present production and the distribution of major fungal metabolites in apple jam and crème fraiche for some additional fungal strains (P. crustosum, P. roqueforti and P. verrucosum on apple jam and P. expansum on crème fraiche). A pilot study investigating the effect of inoculation size on toxin production may have implications for the best inoculum to use in experimental studies.